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EN
Halloysite is commonly occuring in Poland a natural mineral which, due to its structure is very popular among researchers. First of all, the large number of sorption areas and their various selectivity makes the material capable of adsorbing the compounds of different nature at the same time. As a result, there is a lot of possible applications. In addition, ease of functionalization of the surface of the material increases its sorption capacity and makes its more attractive. 
EN
The influence of chitosan content in hydrogel beads on the sorption effectiveness of Reactive Black 5 (RB5) dye from aqueous solutions is presented in the following work. The dry mass of chitosan in the tested hydrogel chitosan sorbents was from 2 to 10%. The influence of pH (4–11) on the sorption effectiveness of RB5 on chitosan hydrogels as well as the sorption capacity of the tested chitosan sorbents in relation to RB5 were studied. The optimal pH of RB5 sorption was determined along with the pH at the potential at zero point charge (pHPZC) of the tested sorbents. The maximum sorption capacity of the tested sorbents, depending on the amount of chitosan dry mass in the hydrogel beads, was determined. The obtained data was fit to Langmuir 1, Langmuir 2, and Freundlich models.
EN
The article presents the effectiveness of orthophosphate sorption from aqueous solutions depending on the deacetylation degree of chitosan flakes. The first stage of the research was to determine the pH value at which the sorption process was the most effective (from the pH range 2–11). In the second stage, research was carried out to determine the maximum sorption capacities of chitosan with deacetylation degrees of 75%, 85% and 90% in relation to PO43-. The highest effectiveness of orthophosphate removal on chitosan, regardless of its deacetylation degree, was obtained at pH 4. At pH 2 and 3, the chitosan flakes dissolved. This study showed that the sorption effectiveness of phosphorus compounds depends on the deacetylation degree of chitosan. Along with the increase in deacetylation degree, the sorption capacity of chitosan also increases in relation to orthophosphates. It is related to the higher number of amino groups in the structure of chitosan, which are responsible for the sorption of pollutants in the form of anions. The maximum sorption capacity of chitosan-DD = 75% in relation to biogen was 5.13 mg/g, chitosan-DD = 85% was 5.65 mg/g, and chitosan-DD = 90% was 5.91 mg/g. After 60 minutes, the desorption process had begun and was most likely caused by an increase in the pH of the solution. Due to chitosan's ability to neutralise the sample and the associated risk of desorption, the time of sorbent contact with sewage cannot be longer than 60 minutes.
EN
This article presents the influence of chitin amination on the effectiveness of RB5 and RY84 dye sorption. For chitin and chitin modified by amination, the optimal pH of sorption and the maximum sorption capacity were determined in relation to two reactive dyes: Reactive Black 5 (RB5) and Reactive Yellow 84 (RY84), differing in the active group and molecular weight. Three sorption models were used to describe the experimental data: Langmuir, Langmuir 2 and Freundlich. The highest sorption capacity was obtained for aminated chitin for both tested dyes: 386.53 mg/g for RB5 and 261.56 mg/g for RY84. In the case of sorption on unmodified chitin, the sorption capacities were lower: up to 235.65 mg/g.d.m. for RB5 and 208.88 mg/g.d.m. for RY84. The modification of chitin by amination has a beneficial effect on the amount of dye adsorbed in the process. The adsorptive capacity increased by 1.6-times in the case of RB5 and 1.25-times in case of RY84.
EN
Poly(2-acrylamido-2-methyl-1-propanesulfonic acid-co-1-vinyl-2-pyrrolidone), P(AMPS-co-VP), hydrogel was prepared by free radical cross-linking polymerization method. Prepared hydrogel was used in the competitive removal of Cd(II), Pb(II) and Cu(II) ions from aqueous solution. The characterization of P(AMPS-co-VP) before and after sorption was carried out by the Fourier transform infrared spectroscopy, thermogravimetric analysis and scanning electron microscopy. Atomic absorption spectrometer was used to found the concentration of metal ions in the aqueous solution. The selectivity of P(AMPS-co-VP) was as follows: Cd(II)>Pb(II)>Cu(II). Kinetic study showed that competitive removal of heavy metal ions on poly(AMPS-co-VP) was in accordance with a pseudo-second-order model.
EN
Here, we report the fabrication of supermacroporous monolith sorbents for acidic dye removal via chitosan cross-linking with ethylene glycol diglycidyl ether (EGDGE) in acidic medium at sub-zero temperature. The developed porous structure with the thickness of polymer walls in the range of a few microns and a high content of primary amino groups determined the high sorption capacity of the sorbents toward Alizarin Red in a broad pH range (2–8). Due to the cross-linking via hydroxyl groups of the chitosan, the static sorption capacity of the fabricated materials was higher than that of chitosan flakes, even for sorbents cross-linked at EGDGE:NH2-chitosan with molar ratio 2:1. The monolith sorbents were mechanically stable and supported flow rates up to 300 bed volumes per hour. The breakthrough curve of Alizarin Red sorption showed that the effective dynamic sorption capacity was 283 mg/g, and 100% of the dye could be removed from the solutions with concentration of 100 mg/L. The monoliths can be regenerated with 0.3s M NaOH solution and used in several consecutive cycles of sorption/regeneration without loss of efficacy.
EN
In the paper sorption capacity of chitosan having a deacetylation degree DD=75%, DD=85% and DD=90% relatively to the Reactive Black 5 were compared. Studies on the effectiveness of the dye sorption were carried out in a wide pH range – from 3 to 11. For each of the tested chitosan sorbents, sorption capacity has been determined. The results were described by isotherms Freundlich and Lagmuir isotherms, and a double Langmuir isotherm. Sorption of Reactive Black 5 most efficiently occurred at pH 4. At pH <4 chitosan sorbents underwent dissolution, regardless of the degree of deacetylation. The efficiency of dye sorption increased with the degree of deacetylation. The sorption capacity calculated after 12 h of the chitosan sorption with DD=75%, DD=85% and DD =90% was, relatively to the Reactive Black 5, respectively 433.03 mg/g and 464.52 mg/g and 532.14 mg/g. The impact of the deacetylation degree on pHZPC (zero point of charge) of the sorbent was also examined. Along with the increase in the deacetylation degree the value of chitosan pHZPC increased as well and at DD=75% DD=85% and DD=90%, pHZPC amounted respectively 7.6, 7.7 and 7.8.
EN
The influence of the degree of deacetylation of chitosan from the range of DD = 75–90% on the effectiveness of sorption of nitrates from aqueous solutions was investigated. The scope of the research included: determining the effect of pH on the effectiveness of N-NO3 binding on chitosan sorbents and determining the sorption capacity of chitosan sorbents with different degrees of deacetylation after 5, 15, 30 and 60 minutes. The effectiveness of sorption of nitrates on chitosan sorbents increased in the series DD=75% < DD=85% < DD=90%. Regardless of the degree of deacetylation, the sorption effectiveness of nitrates on chitosan was the highest at pH 4. The amount of nitrate-related sorbents was the highest after 30 min of sorption. A process time which was too long resulted in desorption of nitrates. The maximum sorption capacity for chitosan with the degree of deacetylation DD = 75, 85 and 90% was 0.59 mg N-NO3/g, 0.60 mg N-NO3/g and 0.87 mg N-NO3/g, respectively.
EN
1,3-propanediol is a promising monomer with many applications and can be produced by bioconversion of renewable resources. The separation of this product from fermentation broth is a difficult task. In this work, the application of cation exchange resin for the separation of 1,3-propanediol from model aqueous solution was examined. The best effect of separation of 1,3-propanediol from glycerol using sorption method was obtained for H+ resin form, although the observed partition coefficient of 1,3-propanediol was low. On the basis of the results of the sorption of 1,3-propanediol, the ionic forms of the resin were selected and used in the next experiments (H+, Ca2+, Ag+, Na+, Pb2+, Zn2+). The best results in ion exchange chromatography were obtained for cation exchange resin in H+ and Ca2+ form. The use of smaller particle size of resin and a longer length of the column allows to obtain better separation of mixtures.
EN
The main goal of this study was the preparation of materials containing phosphoric functionalities on the base of industrial polymer - divinyl rubber and the assessment of their removal efficiency of heavy metals from aqueous solutions. The new method concerns the oxidative chlo-rophosphorylation of divinyl rubber by PCl3 with the following modification of obtained inter-mediates to create -PO(OH)2, -OPO(OH)2 groups in the polymer chain. The obtained modified polymers get some new properties such as complex formation and capability for ion exchange. The nature and distribution of phosphoric functionalities in the polymer were studied by the methods of NMRand FTIR- spectroscopy, thermal analysis and scanning electron microscopy. The sorption properties of synthesized polymers towards some cations (Cu+2, Ni+2, Co+2 and Zn+2) from water solutions have been tested. It has been shown that the metal removal efficiency of prepared material depends on pH of medium, initial concentration and type of metal ions.
12
88%
EN
The effect of pH on copper ions sorption by alginates has been investigated. The granules of the sorbent obtained from sodium alginate (type DMF, manufactured by KELCO) have been applied. By using a new method of gelation a biosorbent containing from 11.3 to 20.3% mas. of alginate has been produced. Investigations have been carried out at a constant temperature of 25°C and the pH values ranging from 3 to 5. The obtained experimental results have been described by the Langmuir equation. It has been found that with the increasing pH of the solution the maximum biosorbent sorption capacity increased.
Nukleonika
|
2015
|
vol. 60
|
issue 4
927-931
EN
The paper reports the adsorption of strontium(II) and americium(III) from aqueous solutions onto calcium alginate (CaA), barium alginate (BaA) and strontium alginate (SrA) beads. Adsorption process was studied in batch experiments as a function of the initial pH of the solution and the contact time. All sorbents were examined by the termogravimetric analysis (TG). Laboratory obtained spherical beads of CaA, BaA and SrA seem to be good metal sorbents from liquid radioactive wastes. A contact time of about 4 h and neutral pH of the initial aqueous solution have been proposed to be optimum conditions for Sr-85 and Am-241 removal from the contaminated solutions using alginate sorbents. Laboratory obtained beads of CaA, BaA and SrA are characterized by the decontamination factor (DF) equal to 85% for Sr(II) and 90% for Am(III).
EN
The aim of this paper was to prepare chitosan microspheres characterised by a narrow dispersion of dimensions, suitable for application for drug delivery systems (DDS). The materials, unmodified as well as functionalised using polyethyleneimine were then used for encapsulation of drug-mimicking dyes. The polymeric beads were prepared by one stage process of membrane emulsification. The encapsulation and then evaluation of the release of an active component was carried out using two cytostatics-mimicking dyes: methyl orange and Congo red. The efficiency of encapsulation changed with a type of microspheres and the type of a dye. The highest sorption towards dyes was revealed by PEI-modified chitosan microspheres. Methyl orange was released with the better efficiency than Congo red from all types of microspheres.
EN
This study examined the effect of salt concentration (NaCl/Na2SO4) on the sorption efficiency of Reactive Black 5 (RB5) dye on chitosan hydrogel granules (CHs). The tested salt concentration was in the range of 0.0 to 0.5 mol/L. The scope of the research included the effect of salinity on RB5 sorption at different pH values (4–11), equilibrium time, and maximum sorption capacity (Langmuir 2 model). At low pH (pH 4, pHpHPZC), an opposite trend was observed (the sorption efficiency of RB5 on CHs increased with increasing salinity). The concentration of salt in the solution did not have a major impact on the equilibrium time of sorption, which depended mainly on the initial pH of the solution (and ranged from 36 to 60 h). The relatively long sorption time resulted from the hydrogel structure of the sorbent used, which slowed the dye absorption ability. The maximum sorption capacity of CHs in relation to RB5 at the optimum pH (pH 4) in the solution without the addition of salt determined after 60 h of sorption was 1.386 mmol RB5/g (1373.5 mg RB5/g). Under conditions of high salinity (0.5 mol Na2SO4/L), at pH 4, the capacity was 17.2% lower (1.148 mmol RB5/g to 1139.7 mg RB5/g), and at pH 11, it was 6.3% higher (1.474 mmol RB5/g to 1460.7 mg RB5/g).
EN
Wide use of bisphenol A (BPA) in production of polycarbonates and plastic food packaging cause increase of concentration of BPA in the environment. Both in surface water, underground water and seawater BPA was frequently detected in different concentrations. Emerging problem is adsorption of BPA on sewage, because it could be considered as an additional source of pollution, if it is used as a fertilizer in agricultural sectors. Absorbed BPA on sewage sludge stays persistent in the environment and generates adverse biological effects in endocrine system. Because of ecological safety, exploration of potential techniques to remove BPA to the level, which does not give adverse effect on natural environment is necessary. In this study the adsorption of BPA from simulated water onto commercial activated carbons was investigated. On the basis of experimental data the kinetics and type of sorption were determined.
PL
Masowe wykorzystywanie bisfenolu A (BPA) do produkcji tworzyw sztucznych i opakowań na żywność powoduje wzrost stężenia tego związku w środowisku. Zarówno wody powierzchniowe, podziemne, jak i morskie ulegają coraz większemu skażeniu bisfenolem A. Niepokojący jest fakt, że BPA obecny w ściekach w znacznym stopniu ulega sorpcji na kłaczkach osadu czynnego, co wskazuje na dodatkowe źródło zanieczyszczenia środowiska tym związkiem. Zasorbowany na osadzie bisfenol A trwale pozostaje w środowisku, wywołując niekorzystne efekty biologiczne głównie o charakterze hormonalnym. Zagrożenie, jakie stanowi ten związek, powoduje konieczność poszukiwania efektywnych metod jego usuwania. W pracy określono możliwość usuwania BPA z roztworów wodnych na krajowych i zagranicznych węglach aktywnych. Na podstawie danych doświadczalnych wyznaczono kinetykę i typ procesu sorpcji.
EN
The efficiency of walnut, pistachio and hazelnut shells to remove three monochlorophenols (2-CP, 3-CP and 4-CP) from aqueous solutions has been investigated. To describe the kinetic data pseudo-first and pseudo-second order models were used. The kinetics data were fitted better into the pseudo-second order model with the coefficient of determination values greater than 0.99. The k2 values increased in the order 4-CP < 3-CP < 2-CP. Sorption was also analyzed as a function of solution concentration at equilibrium. The experimental data received were found to be well described by the Freundlich isotherm equation. Effectiveness of chlorophenols removal from water on the walnut, pistachio and hazelnut shells was comparable. Individual differences in sorption of monochlorophenols were also negligible.
EN
The sorption capacity of glauconite, glauconite immobilised on chitosan hydrogel beads and unmodified chitosan hydrogel beads against Reactive Black 5 and Basic Violet 10 was compared in this article. The effect of pH on the sorption effectiveness of dyes on the tested sorbents was investigated and the sorption capacity of sorbents after 24 and 72 h was determined. Langmuir sorption, double Langmuir and Freundlich isotherms were used to describe the experimental data. The adsorption efficiency of the dyes on sorbents containing chitosan was highest at pH 4. In the case of glauconite, Reactive Black 5 removal efficiency was the highest at pH 3, and Basic Violet 10 removal efficiency was highest at pH 2. The sorption capacity of glauconite immobilised on chitosan hydrogel spheres obtained after 72 h was -656.73 mg/g and -32.77 mg/g for Reactive Black 5 and Basic Violet 10, respectively.
EN
In this article, the sorption properties of chitosan hydrogel beads, beech sawdust and sawdust immobilised on chitosan in relation to Reactive Black 5 (RB5) and Basic Violet 10 (BV10) dyes were compared. In the conducted research, the sorption capacities of the sorbents, sorption pH and the point of zero charge (pHZPC) were determined. For the description of the obtained results, the double Langmuir model has been used. The highest effectiveness of the cationic and anionic dye removal on chitosan hydrogel beads and sawdust immobilised on chitosan was obtained at pH 4, whereas on sawdust, the pH was 3. The best sorbent in relation to the RB5 dye was obtained using chitosan hydrogel beads, and in relation to BV10, it was sawdust. The maximum sorption capacity of chitosan in relation to RB5 was 875.66 mg/g, whereas the sorption capacity of sawdust in relation to BV10 was 30.15 mg/g. The research has shown that the sorbent in the form of sawdust immobilised on chitosan had a high sorption capacity in relation to anionic as well as cationic dyes. Immobilisation of sawdust on chitosan led to the creation of a universal sorbent in relation to cationic and anionic dyes.
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